• 제목/요약/키워드: quantum transport

검색결과 204건 처리시간 0.031초

Magnetic dependence of cyclotron resonance in the electron-piezoelectric phonon interacting materials

  • Park, Jung-Il;Sug, Joung-Young
    • 한국자기공명학회논문지
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    • 제24권1호
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    • pp.16-22
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    • 2020
  • Based on quantum transport theory, we investigated theoretically the magnetic field dependence of the quantum optical transition of quasi 2-dimensional Landau splitting system, in CdS and ZnO Through the analysis of the current work, we found the increasing properties of the cyclotron resonance line-profiles (CRLPs) which show the absorption power and the cyclotron resonance line-widths (CRLWs) with the magnetic field in CdS and ZnO We also found that that CRLWs, γtotal(B) of CdS < γtotal(B) of ZnO in the magnetic field region B < 15 Tesla.

SCH 양자우물 레이저 다이오드의 수송기구와 변조응답 특성에 관한 연구 (A Study on the Transport Mechanism of a SCH Quantum-Well Laser Diode and on the Modulation Characteristics)

  • 김종기;정재용;서정하
    • 대한전자공학회논문지TE
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    • 제37권1호
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    • pp.27-34
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    • 2000
  • 본 논문에서는 SCH 양자우물 구조를 가진 레이저 다이오드에서의 캐리어 수송기구와 변조응답 특성에 대해 고찰하였다. 캐리어 수송구조 고찰을 위해 캐리어 밀도분포및 다이오드전류를 계산하였다. 또한 우물내에서의 캐리어 재결합율을 SCH길이의 함수로 도출하였다. 변조응답 특성에서는 캐리어와 광자에 대한 3쌍의 비율 방정식을 도출, 해석하여 SCH 길이에 따른 변조 대역폭과 완화 진동 주파수, 감쇄 비율과 K-factor의 특성에 대하여 고찰하였다.

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Wigner 함수 모델을 이용한 양자전송의 시뮬레이션 (Simulation of Quantum transport using wigner function model)

  • 김경염;이병호
    • 전자공학회논문지D
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    • 제34D권3호
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    • pp.93-104
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    • 1997
  • Steady-state I-V characteristics of a resonant tunneling diode (RTD) is calculated by numerical analysis using quantum liouville equation based on wigner function which is derived from density operator. Modifications to the conventional discrete model are made to calculate more accurate quantum correlations. It is pointed out that we must include inelastic processes and the resistivity of the contacting layers to get a much more credible potential which can be theoretically obtained from the simple screening theory. The effects of spatially-varying effective mass is also checked briefly.

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Magnetoconductance of a Hybrid Quantum Ring: Effects of Antidot Potentials

  • Kim, Nammee;Park, Dae-Han;Kim, Heesang
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.335.1-335.1
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    • 2016
  • The electronic structures of a hybrid magnetic-electric quantum ring and two terminal conductance taking into account the resonant backscattering via both magnetic and electric edge channels are studied. The hybrid magnetic-electric quantum ring is formed by a magnetic quantum dot combined with an additional antidot electrostatic potential at the center of the dot. Electrons are both magnetically and electrically confined to the plane. The antidot potential repelling electrons from the center of the dot plays an important role in the energy spectra and magnetoconductance. The angular momentum transition in the ground state and the behavior of magnetoconductance due to a change of the antidot potential are shown in comparison with the conventional magnetic quantum dot.

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Controlling Quantum Confinement and Magnetic Doping of Cesium Lead Halide Perovskite Nanocrystals

  • Dong, Yitong;Parobek, David;Son, Dong Hee
    • 한국세라믹학회지
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    • 제55권6호
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    • pp.515-526
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    • 2018
  • Cesium lead halide ($CsPbX_3$) nanocrystals have emerged as a new family of semiconductor nanomaterials that can outperform existing semiconductor nanocrystals owing to their superb optical and charge transport properties. Although these materials are expected to have many superior properties, control of the quantum confinement and isoelectronic magnetic doping, which can greatly enhance their optical, electronic, and magnetic properties, has faced significant challenges. These obstacles have hindered full utilization of the benefits that can be obtained by using $CsPbX_3$ nanocrystals exhibiting strong quantum confinement or coupling between exciton and magnetic dopants, which have been extensively explored in many other semiconductor quantum dots. Here, we review progress made during the past several years in tackling the issues of introducing controllable quantum confinement and doping of $Mn^{2+}$ ions as the prototypical magnetic dopant in colloidal $CsPbX_3$ nanocrystals.

Performance Enhancement of Organic Light-emitting Diodes with an Electron-transport Layer of Bathocuproine

  • Honga, Jin-Woong;Guo, Yi-Wei;Shin, Jong-Yeol;Kim, Tae Wan
    • Transactions on Electrical and Electronic Materials
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    • 제17권1호
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    • pp.37-40
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    • 2016
  • Performance enhancement of organic light-emitting diodes (OLEDs) is investigated in a device structure of ITO/TPD/Alq3/LiF/Al and ITO/TPD/Alq3/BCP/LiF/Al. Here, bathocuproine (BCP) is used as an electron-transport layer. Current density-voltage-luminance characteristics of the OLEDs show that the performance of the device is better with BCP layer than without BCP layer. The current density, luminance, luminous efficiency, and external-quantum efficiency are improved by approximately 22%, 50%, 2%, and 18%, respectively. Since the BCP layer lowers the electron energy barrier, electron transport is facilitated and the movement of hole is blocked as the applied voltage increases. This results in an increased recombination rate of holes and electrons.

자기조립단분자막을 이용한 양자점 발광다이오드의 전하 균형도 개선 (Improved charge balance in quantum dot light-emitting diodes using self-assembled monolayer)

  • 박상욱;정운호;배예윤;임재훈;노정균
    • 전기전자학회논문지
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    • 제27권1호
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    • pp.30-37
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    • 2023
  • 양자점 발광 다이오드(QD-LED)의 효율과 안정성 향상을 위해서 QD 발광층에 주입되는 전하의 균형을 이루는 것은 필수이다. 산화 아연(ZnO)은 최신 QD-LED에서 전자수송층(electron transport layer, ETL)을 구성하기 위해 가장 많이 사용되고 있으나, ZnO의 자발적인 전자 주입은 QD-LED의 성능을 크게 열화시키는 과도한 전자 주입을 유발한다. 본 연구에서는 자기조립단분자막(self-assembled monolayer, SAM) 처리를 통해 ZnO의 전자 주입 특성을 조절하여 QD-LED의 성능을 향상시켰다. 전하 균형도를 향상시킨 결과, SAM을 처리한 QD-LED는 SAM을 처리 안한 소자와 비교하여 내부 양자 효율(external quantum efficiency, EQE)이 25%, 최대 휘도는 200% 향상되었다.

양자점과 정공 수송 물질의 혼합층을 사용한 양자점 전계발광 소자의 특성 연구 (A Study on the Characteristics of a Quantum Dots Light-Emitting Diodes Using a Mixed Layer of Quantum Dots and Hole Transport Materials)

  • 윤창기;오성근;김지완
    • 마이크로전자및패키징학회지
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    • 제28권4호
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    • pp.69-72
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    • 2021
  • Quantum Dot Light-Emitting Diodes (QLEDs)는 제조 공정이 용액 공정을 기반으로 하기 때문에 잉크젯 공정에 쉽게 적용할 수 있다. 하지만 QLED의 적층은 서로 다른 용매를 사용하는 직교 공정이 필요하기 때문에 잉크젯 인쇄 공정이 더 복잡하며 비용이 상승한다. 따라서 한 번의 공정으로 두 개의 층을 증착하면 제조 단계를 줄일 수 있어 공정 시간이 절감된다. 이 연구에서 우리는 QD와 정공 수송 재료의 혼합물을 사용하여 standard 구조의 QLED를 제작하였다. TFB와 QD를 클로로벤젠에 분산시켜 혼합층에 사용하였고, 소자는 45,850 cd/m2의 최고 휘도를 나타내었다. 이 연구는 잉크젯 프린팅 공정을 적용하여 전계발광 장치를 제작할 수 있는 가능성을 확인하였다.

구속 포텐셜의 전자-압전 포논 상호 작용에 따른 GaAs의 자기장 의존 특성 (The Magnetic Field Dependence of the Confinement Potential due to the Interaction of Electron and Piezoelectric Phonon in GaAs Semiconducting Materials)

  • 이수호;김해재;주석민
    • 전기학회논문지P
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    • 제67권3호
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    • pp.149-154
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    • 2018
  • We consider the system is subject to the linearly polarized oscillatory external field. We study the optical quantum transition Line shapes(QTLS) which show the absorption power and the quantum transition line widths(QTLW) of electron-piezoelectric phonon interacting system. We analyze the magnetic field dependence of the QTLS and the QTLW in various cases. In order to analysis the quantum transition, we compare the magnetic field dependence of the QTLW and the QTLS of two transition process, the intra-Landau level transition process and the inter-Landau level transition process.